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Hajime Sakaguchi Hiromi Hagiwara Yoshihiro Fukumori Yutaka Tamaura Minoru Funaki Shigehisa Hirose 《FEMS microbiology letters》1993,107(2-3):169-173
Abstract The magnetic bacterium Magnetospirillum magnetotacticum prefers a microaerobic habitat and should be able to sense oxygen. Therefore, the bacterium was cultured under atmospheres containing 0–5% O2 and analyzed for oxygen-dependent changes in the levels of its protein components by sodium dodecyl sulfate-polyccrylamide gel electrophoresis (SDS-PAGE). The analysis revealed a marked anaerobic induction of a 140-kDa protein, which was suppressed when M. magnetotacticum was switched from microaerobic (<1% O2 ) to aerobic (>1% O2 ) growth conditions. Although its function remains to be determined, the 140-kDa protein may serve as a useful tool to gain insight into the physiology of the organism. 相似文献
3.
Junko Maeda Charles R. Yurkon Yoshihiro Fujii Hiroshi Fujisawa Sayaka Kato Colleen A. Brents Mitsuru Uesaka Akira Fujimori Hisashi Kitamura Takamitsu A. Kato 《PloS one》2015,10(12)
When energetic particles irradiate matter, it becomes activated by nuclear reactions. Radioactivation induced cellular effects are not clearly understood, but it could be a part of bystander effects. This investigation is aimed at understanding the biological effects from radioactivation in solution induced by hadron radiation. Water or phosphate buffered saline was activated by being exposed to hadron radiation including protons, carbon- and iron-ions. 1 mL of radioactivated solution was transferred to flasks with Chinese hamster ovary (CHO) cells cultured in 5 mL of complete media. The induction of sister chromatid exchanges (SCE) was used to observe any increase in DNA damage responses. The energy spectrum and the half-lives of the radioactivation were analyzed by NaI scintillation detector in order to identify generated radionuclides. In the radioactivated solution, 511 keV gamma-rays were observed, and their half-lives were approximately 2 min, 10 min, and 20 min. They respectively correspond to the beta+ decay of 15O, 13N, and 11C. The SCE frequencies in CHO cells increased depending on the amount of radioactivation in the solution. These were suppressed with a 2-hour delayed solution transfer or pretreatment with dimethyl sulfoxide (DMSO). Our results suggest that the SCE induction by radioactivated solution was mediated by free radicals produced by the annihilated gamma-rays. Since the SCE induction and DMSO modulation are also reported in radiation-induced bystander effects, our results imply that radioactivation of the solution may have some contribution to the bystander effects from hadron radiation. Further investigations are required to assess if radioactivation effects would attribute an additional level of cancer risk of the hadron radiation therapy itself. 相似文献
4.
Yoshinari Maeda Kiyoshi Yoshimura Hiroto Matsui Yoshitaro Shindo Takao Tamesa Yukio Tokumitsu Noriaki Hashimoto Yoshihiro Tokuhisa Kazuhiko Sakamoto Kouhei Sakai Yutaka Suehiro Yuji Hinoda Koji Tamada Shigefumi Yoshino Shoichi Hazama Masaaki Oka 《Cancer immunology, immunotherapy : CII》2015,64(8):1047-1056
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D X Hou Y Maeda S Okamoto T Hashiguchi 《Comparative biochemistry and physiology. B, Comparative biochemistry》1990,97(4):761-766
1. A chymotrypsinogen from pancreas of Japanese quail (Coturnix coturnix japonica) was purified by acid extraction, salt fractionation and chromatographic separation on CM-cellulose and Sephadex G-100, and gave a single protein band on SDS-PAGE. 2. Quail chymotrypsinogen had a mol. wt of 26,100 calculated from amino acid composition data, an isoelectric point of 7.68, a Km of 3.1 mM and K0 of 40.7 sec-1 for tyrosine ester substrate. 3. The activated chymotrypsinogen of quail had a maximum activity at pH 7.0-8.0 and at 45 degrees C, and was stable at pH 4.0-6.0 below 55 degrees C. 4. Comparison of quail and bovine chymotrypsinogens indicates that the activities of the enzymes from quail and bovine are more constant than their physical characteristics. 相似文献
7.
We examined the effects of a sulfonylurea herbicide, chlorsulfuron, which is known as a potent inhibitor of plant cell division,
on morphogenetic cell division and disorganized cell division using the culture system of multiple shoot primordia and callus
of Passiflora edulis. The multiple shoot primordia tissue treated with chlorsulfuron failed to achieve shoot morphogenesis, and a large part of
the tissue was necrotized during the posttreatment culture, even when it was washed and transferred to chlorsulfuron-free
medium. The inhibition of Passiflora shoot morphogenesis by chlorsulfuron was not reversed by the simultaneous addition of branched amino acids, which are known
to reverse the inhibitory effect of chlorsulfuron. In contrast, the same treatment of chlorsulfuron on the callus did not
kill the cells, although the growth resumption was retarded by a prolonged lag period. The addition of branched amino acids
enhanced the recovery growth of the chlorsulfuron-treated callus. These results suggest that the inhibition of disorganized
cell division (callus growth) by chlorsulfuron is reversible, whereas morphogenetic cell division (shoot morphogenesis), which
is under complex regulation, is inhibited irreversibly by chlorsulfuron. Qualitative differences between morphogenetic cell
division and disordered simple proliferative cell division are discussed.
Received November 17, 1997; accepted June 4, 1998 相似文献
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9.
Hiroki Yanagida Takefumi Morita Juhyon Kim Keitaro Yoshida Kazuki Nakajima Yutaka Oomura Matthew J. Wayner Kazuo Sasaki 《Peptides》2008,29(6):912-918
Ghrelin is an endogenous ligand for the growth hormone (GH) secretagogue (GHS) receptor (GHS-R) and a potent stimulant for GH secretion even in infantile rats before puberty. Although the ventromedial nucleus of the hypothalamus (VMH) might be a site of action for ghrelin to induce GH release, the electrophysiological effect of ghrelin on VMH neurons in infantile rats remains to be elucidated. Thus, the purpose of the present study was to investigate the effect of ghrelin on VMH neurons using hypothalamic slices of infantile rats. Ghrelin excited a majority of VMH neurons in a concentration-dependent manner. VMH neurons that were excited by GH releasing peptide-6 (GHRP-6), a synthetic GHS, were also excited by ghrelin and vice versa. Repeated application of ghrelin to the same VMH neuron decreased progressively the excitatory responses depending on the number of times it was administered. The excitatory effect of ghrelin on VMH neurons in normal artificial cerebrospinal fluid (ACSF) persisted in low Ca2+-high Mg2+ ACSF. The present results indicate that (1) ghrelin excites a majority of VMH neurons dose-dependently and postsynaptically and (2) the excitatory effects of ghrelin are mimicked by GHRP-6 and desensitized by repeated applications of ghrelin. 相似文献
10.
After E. coli cells (WP2 and WP2uvrA) were treated with chemical mutagens (methyl methanesulfonate, MMS; N-methyl-N-nitrosourea, MNU; 4-nitroquinoline 1-oxide, 4NQO) in 1/15 M phosphate buffer, the mutability of the treated cells plated on a D2O-agar plate was compared with that plated on an ordinary H2O-agar plate. The mutation frequency decreased more or less on the D2O-agar plate. The D2O-substitution effects, as termed by the relative mutation frequencies (MFD2O/MFH2O), are 0.92 for MMS, 0.29 for MNU, and 0.42 for 4NQO in WP2, and 0.68 for MMS, 0.49 for MNU, and 0.16 for 4NQO in WP2uvrA. The D2O effect seemed to be partly related to the function of the uvrA gene-associated products. The pH dependence of mutability was discussed in connection with the D2O-substitution effect. 相似文献